The purpose of this K01 proposal is to gain training and experience using online social networks to increase HIV prevention communication and behavior change. This proposal seeks to determine the acceptability, feasibility, and preliminary effectiveness of using online social networks to scale peer community leader models to increase HIV prevention within African-American and Latino men who have sex with men (MSM). Community-based behavior change models such as the peer community leader model have been proven to increase HIV prevention behaviors. Social networks such as Facebook.com may be a cost-effective platform for scaling community-based models. Although primarily upper middle-class White populations used the Internet in its early years, Internet use within African-American and Latino households has recently increased dramatically, especially on online social networks such as Facebook.com. People using the Internet may be at the highest risk for contracting HIV and are using novel Internet approaches to find sex partners, such as through online social networks. No published studies have looked at whether community-based HIV prevention models can be scaled using online social networks, making this an important feasibility study. We propose the following specific aims to address this research: Specific Aim 1: Use qualitative methods to explore whether and how online social networks can be used for HIV prevention in African American and Latino MSM. Specific Aim 2: Assess the best communication methods for using online social networks for HIV prevention and use this knowledge to create 2 structured guides (one guide for African American MSM and one guide for Latino MSM) for peer leaders to disseminate HIV prevention behavior change information to African American and Latino MSM. Specific Aim 3: Design a pilot study to assess the feasibility, acceptability, and preliminary effectiveness of using online social networks to increase testing and HIV prevention behaviors in African American and Latino MSM. The pilot data collected from this study will be used to develop an R01 proposal for a larger randomized trial designed to assess whether online social networks can be used to scale community-based prevention interventions to increase testing and decrease HIV transmission within communities at disproportionately high-risk for HIV.